Jarring apparatus for molds



Dec. 13, 1955 R. H. WIEHSNER 2,726,428

JARRING APPARATUS FOR MOLDS Filed Sept. 11, 1951 2 Sheets-Sheet l INVENTOR. RnYmoNo H-WIEHSNER YBYMM-Q ATTORNEY United States Patent O JARRING APPARATUS FOR MOLDS Raymond H. Wiehsner, Philadelphia, Pa., assignor to The Tabor Manufacturing Company, Philadelphia, Pa., a corporation of Pennsylvania Application September 11, 1951, Serial No. 246,021

2 Claims. (Cl. 22-45) This invention relates generally to foundry machines of the type incorporating mold supporting and jarring members, the latter being operative to ram the mold supported by the former, and is more particularly concerned with an improved mechanism interconnecting the aforementioned members in a manner affording increased certainty as to the functioning of such a mechanism.

In making a mold, it is common foundry practice to place the pattern in a flask and to secure both to a rollover plate, to fill the flask with molding material and to ram the mold by jarring the rollover plate. The latter operation is commonly performed by a jarring member having a jarring head disposed beneath the rollover plate and actuated by a vertically reciprocating piston. It is known that jarring of the rollover plate is more effective to ram the mold when the rollover plate and the jarring head are secured to one another during the jarring operation. However, known mechanisms for accomplishing this end have not been entirely satisfactory, because they do not function with the desired degree of certainty to release the rollover plate from the jarring head when the ramming is completed.

Accordingly, it is an object of this invention to provide a foundry machine having mold supporting and jarring members with a novel mechanism which, while effective to lock the aforementioned members together during the jarring operation, affords a minimum of resistance to the release thereof from one another at the conclusion of the jarring operation.

This invention, therefore, may be considered as comprising the various features of construction and/or combination affording the above stated and other objects and advantages as hereinafter more particularly pointed out in the following detailed description and appended claims, reference being had to the accompanying drawing of an illustrative apparatus, in which:

Figure 1 is a perspective view of an apparatus incorporating the present invention;

Figure 2 is a plan view on line 2-2 of Figure 1;

Figure 3 is an enlarged plan section on line 3-3 of Figure Figure 4 is a side elevation on line 4-4 of Figure 1;

Figure 5 is an enlarged section on line 5-5 of Figure 2 showing the rollover plate and the jarring head engaged for movement together;

Figure 6 is similar to Figure 5 but shows the rollover plate and the jarring head disengaged for independent movement thereof;

Figure 7 is an enlarged section on line 7-7 of Figure 5; and

Figure 8 is an enlarged detail view of a locking element I fully engaged with its keeper element.

Referring particularly to Figures 1 and 4, it will be seen that the apparatus chosen to illustrate the present invention is a portable jar, rollover and power draw machine for making molds, the machine being of a type commonly used in foundries. The machine is provided with an elongated frame 11 having front and rear end 2,726,428 Patented Dec. 13, 1955- portions supported respectively on widely spaced ground engaging wheels 12-12 and 13-13, and a rollover plate 14 and a part 16 for jarring the same are carried by frame 11. It will be understood, of course, that the machine is provided with suitable controls (not shown) for the operation of rollover plate 14 and jarring part 16.

The rollover plate 14 is a generally rectangular member and normally is disposed over the front end portion of frame 11, being positioned horizontally, and transversely relative to the longitudinal axis of the machine at a convenient working distance from the ground, and being suitably connected to frame 11 for being rolled over degrees to a position over the rear end portion of frame 11.

The jarring part 16 comprises a piston 17 and a jarring head 18, which may be considered a part of the piston 17. The jarring head 18 is a generally rectangular member having an opening 19 formed in a centrally disposed portion thereof, and the piston 17 is an elongated member circular in transverse cross-section and having a reduced upper end portion fitted into the opening 19 and peened over, as at 21, to securely hold jarring head 18 in position. The piston 17 is carried by the front end portion of frame 11 and is disposed for vertical reciprocal movement within a fluid-pressure cylinder 18 suitably mounted upon the frame 11 beneath the rollover plate 14, the jarring head 18 being positioned thereby in a horizontal position immediately beneath rollover plate 14.

Referring particularly to Figures 2, 5 and 6, it will be seen that jarring head 18 is provided with a pair of chambers 22-22, one on each side of piston 17. Each chamber 22 is elongated and circular in transverse cross-section and accommodates a horizontally slidable locking element or pin 23, each of which is in the form of an elongated element having reduced opposite end portions 24 and 26. The reduced end portion 26 of each pin is threaded and mounts a washer 27, a spacer 28 and nuts 29, the washer 27 being slidably fitted in chamber 22 and retained on portion 26 by the spacer 28 and nuts 29.

A guide plate 30 is rigidly secured to each end of the jarring head 18, as by bolts 31, and is disposed thereby at the outer end portion of chamber 22, the outer reduced end portion 24 being slidably received within a tubular barrel portion 32 formed in the guide plate 30.

The main body portion of pin 23 mounts a collar 33 disposed thereon to abut the washer 27, and also mounts a compression spring 34 between sleeve 30 and collar 33. The extreme outward end portion of pin 23 is tapered, as at 36, the extended tapered surfaces preferably forming an included angle of 60 degrees, as best shown in Figure 8. A pair of keeper elements or brackets 37-37 are rigidly secured to the bottom of rollover plate 14 by bolts 38 and are disposed thereby on opposite sides of the jarring head 18 in proximate relation to the pins 23-23.

Each bracket 37 has a horizontally disposed leg through which bolts 38 pass and a vertically disposed leg depending therefrom and having a horizontally elongated slot 39 formed therein, the top and bottom edges of which are oppositely tapered to form an included angle of preferably 40 degrees. It will be noted that the'horizontal central axis of the slots 39-39 is disposed somewhat above the corresponding axis of the pins 23-23 so that as the latter shift outwardly the bottom surfaces of their tapered outer ends 36-36 respectively engage the bottom edges of the slots 39-39 and wedge the piston assembly, including the jarring head 13, into locked engagement with the rollover plate 14.

The inner end portions of chambers 22-22 communicate through passages 41-41 with an internal chamber 42 formed in the piston 17, which chamber 42 is supplied with compressed air by way of an inlet port 43 in communication with a supply line 44.

In the normal operation of the machine, a pattern is.

placed in a flask and both are placed on the rollover plate 14 and suitably secured thereto. Molding material is then placed in the flask over the pattern and the whole is pneumatically jarred to ram the mold. The jarring is effected by piston 17, which acts vertically with a reciprocating movement, being actuated by suitable pneumatic means. The jarring is transmitted to the mold through the jarring head 18 and the rollover plate 14, which are locked together during the jarring operation by means of the pins 23-23 which are shifted outwardly under pneumatic pressure to respectively engage the slotted brackets 37- 37 fixed to the rollover plate 14.

This action is effected when air is supplied for actuation of piston 17, the compressed air being then simultaneously supplied to chambers 2Z22 through air supply line 44 and passages 43, 42 and 41- 11. The air pressure acting against the washers 27-27 shifts pins 2323 from the position of Figure 6 to that of Figure 5. The shifting movement takes place against the action of springs 3434, and, of course, washers 2'7 27 and reduced portions 24-24 slide respectively in chambers 22-22 and sleeves 303fl. When the jarring operation is completed and the air pressure is relieved, the action of springs 34-34 shifts pins 23-23 back to the position of Figure 6. It will be understood that in the outwardly shifted position of Figure the tapered end portions of pins 2 3 engage the tapered openings 39 39 in brackets 3737 for locking the jarring head 18 and the rollover plate '14 together for simultaneous movement during the jarring operation, and that in the inwardly shifted position of Figure 6 the jarring head 18 and the rollover plate 14 are disengaged for relative independent movement.

Now referring particularly to Figures 5 to 7, it Will be seen that the tapered Openings 3939 are elongated and oversized. Also, it will be noted that since the included angle of the extended tapered surfaces of the outer end portions of each of the pins 23=-3 is greater than the included angle of the extended tapered surfaces of the elongated slots 3939, the bottom edges of the tapered surfaces of pins 2323 and of the slots 3939 which respectively engage one another are angularly related to provide, e. g., an angle of degrees therebetween, as plainly shown in Figure 8. In view of the foregoing, it should be apparent that the areas of contact between tapered surfaces 3636 of pins 23-23 and the tapered surfaces of slots 3939 are negligible, and that the contact therebetween may be said to be a point contact. It is this point contact as distinguished from line contact or contact over a comparatively large area which is responsible for the mechanism of the present invention operating with uncommon certainty. The point contact inherently affords a minimum of resistance to inward shifting movement of pins 23-23 when the air pressure is relieved in the proper timing of the machine.

It should be obvious now that a jar, rollover and power draw machine for making molds has been provided with a novel mechanism for locking the rollover plate and jarring head together for simultaneous reciprocating movement during the jarring operation, the aforementioned mechanism acting with an uncommon degree of certainty in releasing the rollover plate from the jarring head for independent movement of the former when the jarring operation is completed.

Although the apparatus herein disclosed as embodying the invention has particular utility in the construction of machines for use in making molds, certain features are of more general application, and, therefore, it is not intended to limit the invention to the exact construction and combination herein shown and described for purposes of illustration as various modifications within the scope of the appended claims may occur to persons skilled in the art.

What is claimed as new and useful is:

1. In a machine for use in making molds, said machine comprising a mold-supporting member having a tapered opening formed therein, a vertically reciprocable part for jarring said mold supporting member to ram said mold, an elongated locking element having a tapered end portion and being carried by said reciprocable part and mounted for shifting movement relative thereto, means for actuating said reciprocable part and shifting said locking element so that said tapered end portion of the latter engages the tapered opening in said mold supporting member, said tapered end portion and opening having outwardly diverging surface portions, and said engagement being effective to secure said mold supporting member to said reciprocable part during the jarring operation, and being characterized by point contact between said locking element and the edge defining the opening in said mold supporting member, and means for disengaging said locking element from said mold supporting member when th jarring operation is completed.

2. In a machine for making molds, said machine comprising a rollover plate for supporting a mold, a vertically reciprocable piston disposed therebeneath for jarring said rollover plate to ram said mold, a pair of keeper brackets fixed relative to said plate and having portions depending therefrom and disposed in parallel vertical planes on opposite sides of said piston, said depending portions having tapered openings formed therein, a pair of elongated locking pins having tapered end portions and being carried by said piston on opposite sides thereof between said brackets and being mounted for shifting movement relative thereto, means for actuating said piston and shifting said pins away from said piston so that the tapered end portions of said pins engage the tapered openings in said depending portions of the brackets, said tapered end portions and openings having outwardly diverging surface portions, and said engagement being effective to secure said plate to said piston during the jarring operation, and being characterized by point contact between said tapered end portions and the lowermost portions of the edges defining the openings in said plate, and means for disengaging said pins from the brackets when said jarring operation is completed.

References Cited in the file of this patent UNITED STATES PATENTS 1,216,750 Tscherning Feb. 20, 1917 1,517,797 Neesham Dec. 2, 1924 1,638,665 Lewis Aug. 9, 1927 1,746,219 Lewis Feb. 4, 1930 FOREIGN PATENTS 186,379 Great Britain Sept. 25, 1922 103,698 Switzerland Mar. 1, 1924 

